Carburetor rebuild questions; jet kit or just emulsion tubes.

[tbyte]

I am presently in the process of removing and rebuilding my carburetor.   The reason for the rebuild is that my mileage has gone south.   The bike is largely stock but for shortened and cored cans.  Though I bought the FP jet kit years ago should I bother to install it or just change the emulsion tubes /reset the float height/general cleaning?   I didn't want to open the airbox or remove snorkels.
    Secondly, I am disassembling as per instructions at ducati suite.  I have remove the vent and fuel lines and flipped the carbs.   However there is not enough slack to remove the cables from the holes.  I am guessing that the correct order is to loosen cable adjusters first then remove cables from holder bracket and then remove cable ends from pulley.  I will try again after coffee.  Thanks for any help.

[koko64]

Servicing carbs is a good idea often neglected.

With a stock motor and airbox, and open pipes, I would use the FP jet kit and use the jets and needle position for that set up. Your mufflers are not only cored, but shorter. Even on a stock motor you can get better performance and warm up with a good jet kit.

If your mileage had gone south then definately fit new emulsion tubes as they do wear oval. Buy the FP emulsion tubes, as many say they last longer than the stockers.

Setting the float and generally cleaning the carbs is a good idea.
Some modern fuels are aimed more at fuel injection requirements and not at carbs. It seems the additives that help clean injectors under 40-50 psi can clag up carbs at 3 psi. A can of good carb cleaner is needed, but dont spray it on the rubber diaphrams in case it eats them.

Take your time setting the float just right. They are often out of spec from the factory and each carb set different to the other! 14mm is the float level. Follow the Ducatisuite instructions closely making sure not to depress the springs in the float needles when they touch the float valve.

Yeah it's important to have enough slack to get the cables off.

Good luck and let us know how it goes.

[motoxmann]

yes definitely replace the emulsion tubes, they are almost definitely beyond worn out causing a rich condition. as said above, get the FP tubes, they are nickel plated which is what makes them last so incredibly much longer.
also yes use the jet kit. I'd suggest a 42.5 pilot jet, 14mm float height (VERY important as mentioned above!), needles at 3rd notch from top, and a 125 main jet. fuel screws 2.5-2.75 turns out.

[tbyte]

Thank you for the replies they are helpful.  I am going with the #45 pilot jet, #137.5 main jet and the circlip three notchs from top of new needle.  It is what my kit came with.  Probably this is a stupid question but how important is cleaning the mating surfaces of the float bowl and jet holder?  I wish to reuse those gaskets and doubt I can remove and reinstall them without ripping.  It would make job easier.

[motoxmann]

My 2000 still has the original gaskets that seal perfectly. I've removed the gaskets several times with no issues and cleaned the surfaces.

You may find that the 45 pilot and 137.5 main are too rich for your setup. I'd actually start with the stock 40 pilot, screws 4 turns out, FP needles at 2nd or 3rd position from top, and 135 main. And use the FP springs.
The fp kit should have come with a 135 main

[tbyte]

Thanks motoxmann I was overly cautious about the gaskets.  It was no problem.  As to the pilot jet I had contacted Mark at FP and it was his opinion that if the floats are properly set the 42.5 will cause a lean surge at 3K rpm.  Anyway, I will find out.  Also one of the idle mix screws will not budge and was already chewed up.  I have tried penetrating oil and tapping with no luck.  Next is the heat. 

[motoxmann]

try a reverse drill bit. not an easy-out, but an actual reverse drill bit. dont drill too deep though. if that doesnt work, then try an easy-out in the hole that was drilled

as for what mark said, because he said it I guess it's worth a shot.
I have a 42.5 pilot installed in mine though, screws at 3.5 turns out, and I have a much more free-flowing setup, and it's rock solid smooth at 3k cruising throttle and lower throttle. (2k-2500 is a hair rough though at light throttle, so I may try the 45)

[motoxmann]

any luck on that mix screw?

fyi, a couple things here:
(my floats are at factory 14mm, set properly by using the float bowl mounted sideways to hold the float bracket in it's proper position)
-I installed the 45 pilot in my bike today, and it did definitely make it run smoother at lower rpms and a hair snappier off throttle. with the stock 40, and the 42.5 though, I was able to disable each cylinder individually by closing the mix screw so I could properly determine the best setting for the other side. with the 45 installed it still provided some fuel when the screw was totally closed, so it made it tough to determine the best screw setting. with the 40, my best setting was 4.5 turns out. with the 42.5 my best setting was 3.5 turns out. with the 45's now installed, at first I thought 2.5 turns out was best, but the exhaust still smelled rich so I set it to 2.0 turns out and the exhaust still smells a hint rich but it's rock solid smooth at idle. I'll see what happens later tonight when it cools off to about 55F, cuz right now it's about 80F.
-my bike previously had dynojet needles, springs, and main jet installed. I've heard a few people say they like the dynojet needles over the factorypro needles. I actually compared them today, not sure why I didnt before. sure enough, I strongly prefer the profiles of the dynojet needles, based only on visual comparison. the dynojet needles have a longer profile, less of an angle, with the taper starting earlier in the slide's rise. the factorypro needles have a more aggressive angle, a shorter profile, and start way later in the slide's risen position, meaning the slide is able to move almost 1/4 of the way up before the needle even begins to taper and let fuel seep through. this might have been part of why I was previously running a bit rough at lower rpms and lower throttle positions. I was originally planning to raise the FP needles one notch (was at #3 position, planned to go to #4), but after visually comparing the needles, I decided to put the dynojet needles back in at position #3. sure enough, I gained quite a large chunk of snap and power from 3k-6k, and it's much smoother at all rpms. before with the FP needles, certain rpms were rougher (seemingly lean) and other rpms were smooth but lacking power (seemingly rich). now with the dynojet needles, it seems pretty dead nut perfect everywhere that the needles are effective.
-I installed brand new nickel plated emulsion tubes from FP. had the FP kit installed for about 500 miles. upon disassembly today, the NEEDLES ARE WORN! but the tubes are fine. needles are frickin expensive, tubes are cheaper. so I'll be taking a peek at the dynojet needles in 500 miles to see how they hold up. if those needles wear too, I'm throwing the FP emulsion tubes in the trash and buying stock tubes, as the dynojet needles had ZERO wear with stock tubes.
-I previously had installed the 137.5 main jet. it seemed to be lacking a bit up top, so I went to the 140 main. it's really hard to tell if it's the same or worse up top now with the 140 though because I gained so much midrange. It actually seems like I lost power up top and that it's now running a bit rich up top, but it may just be the same and smoother but following the higher midrange power, throwing off my comparison abilities. I'll wait til tonight on this too to see if it runs noticeably better at high rpm when it's 20-30 degrees colder out. if so, I'll know it's rich, and I'll throw the 137.5 back in.
-the factorypro slide springs are waaaay better than the dynojet springs

but yeah, I vote 45 pilot for sure, just expect to use a really low screw setting for it to idle well.

[tbyte]

I did not get mixture screw out.  I had to get bike out of where she was and rushed her back together.  I am sure I will have it apart again soon anyway for the throttle is sticking.   Later today, after adjusting cables, I will fire her up for the first time.
     Re. float height, I also used the FP tilt method.  It appeared on ducatisuite that he measured with with carbs flat on table.  I tried both ways and there was a difference.

I stayed with original springs as my kit was missing one.
Good to know on the #45 pilot.

[motoxmann]

Re. float height, I also used the FP tilt method.  It appeared on ducatisuite that he measured with with carbs flat on table.  I tried both ways and there was a difference.

good, the tilt way is the right way. flat on a table is incorrect because the weight of the float compresses the needle spring giving a false reading.
as defined by the proper way to adjust it, you measure the float height at the position where the needle is closed and floats touching the needle spring but NOT compressing the spring, only touching it. so yeah you did it correctly, and yes there is a significant difference between tilt and flat